The food/beverage processing/warehouse industries utilize a wide variety of sealed containers and rooms requiring specialized doors for access or entry. The various types of sealed containers and rooms include coolers, freezers, industrial buildings, constant temperature and humidity rooms, ripening rooms, clean rooms and the like. Most of the above applications have specialized doors which require the emergency venting of smoke in the event of a fire. The same specialized door which provides for venting of smoke in the event of a fire may also be used to provide access to the room for the fire fighting personnel. When the container or room utilizes a hatch type of door for this purpose, design problems for the door may be incurred, especially when the door is to be used for a cooler and/or freezer.
While there are a number of emergency smoke hatch doors available today, none of the these doors are effective when the insulation requirements for a cooler or freezer need to be considered. The emergency smoke hatch doors available today are available with only some light degree of insulation. The door requirements for a cooler/freezer include insulation requirements of 4, 5, 6 inches or more of insulating material. When this additional insulation material is added to today's emergency smoke hatch doors, the added weight increases the loading placed on the operating mechanisms which open the door during emergencies. It is found that the existing smoke hatch door operating mechanism designs cannot withstand the stresses imposed by the additional load imposed by doors incorporating added insulation. The existing operating mechanism for emergency smoke hatch doors are normally located inside of the hatch or inside the room or container. Redesigning these existing smoke hatch mechanisms to carry the increase of weight results in cumbersome components that take up additional interior space and restrict access to the interior of the room or container due to their larger size. In addition, the larger mechanisms reduce the venting ability of the door and are expensive to manufacture, install and maintain.
Accordingly, it is desirous to provide a smoke hatch operating mechanism which is capable of operating heavier weight insulated doors without taking up additional space, restricting access to, or venting of the interior of the container or room. The operating mechanism should be relatively light weight, inexpensive to manufacture, install and maintain.